Valve assemblies for viscous fluid dispensers are known from U.S. Pat. No. 6,003,731. FIGS. 16 and 19a-19d of the '731 patent show a pumping arrangement (117) adapted to draw fluid from a package (101) and subsequently expel the fluid in accurate dosages.
However, the valve assembly disclosed in the '731 patent is prone to clogging and therefore can be unreliable and require frequent maintenance procedures. Further, the valve assembly disclosed in the '731 patent includes only one outlet opening or channel and therefore the dispensing apparatus of the '731 patent can perform at only limited dispense rates.
Therefore, there is a need for an improved valve assembly for liquid dispensers which are more reliable, require less maintenance and which are capable of dispensing at slower, more accurate dispense rates and faster dispense rates.